Creates 1 or 2 textures with the same dimensions/format. If the RHI supports textures that can be used as both shader resources and render targets, and bForceSeparateTargetAndShaderResource=false, then a single texture is created. Otherwise two textures are created, one of them usable as a shader resource and resolve target, and one of them usable as a render target. Two texture references are always returned, but they may reference the same texture. If two different textures are returned, the render-target texture must be manually copied to the shader-resource texture.